const MIN_DISTANCE = 10

function getDirection(x, y) {
	if (x > y && x > MIN_DISTANCE) {
		return 'horizontal'
	}
	if (y > x && y > MIN_DISTANCE) {
		return 'vertical'
	}
	return ''
}

export default {
	methods: {
		getTouchPoint(e) {
			if (!e) {
				return {
					x: 0,
					y: 0
				}
			}
			if (e.touches && e.touches[0]) {
				return {
					x: e.touches[0].pageX,
					y: e.touches[0].pageY
				}
			}
			if (e.changedTouches && e.changedTouches[0]) {
				return {
					x: e.changedTouches[0].pageX,
					y: e.changedTouches[0].pageY
				}
			}
			return {
				x: e.clientX || 0,
				y: e.clientY || 0
			}
		},
		resetTouchStatus() {
			this.direction = ''
			this.deltaX = 0
			this.deltaY = 0
			this.offsetX = 0
			this.offsetY = 0
		},
		touchStart(event) {
			this.resetTouchStatus()
			const touch = this.getTouchPoint(event)
			this.startX = touch.x
			this.startY = touch.y
		},
		touchMove(event) {
			const touch = this.getTouchPoint(event)
			this.deltaX = touch.x - this.startX
			this.deltaY = touch.y - this.startY
			this.offsetX = Math.abs(this.deltaX)
			this.offsetY = Math.abs(this.deltaY)
			this.direction = this.direction || getDirection(this.offsetX, this.offsetY)
		}
	}
}